Cannot stop subscriber #2103

If we create a subscriber using with FixedChannelProvider and FixedExecutorProvider and do this

subscriber.startAsync().awaitRunning();
System.err.println("running");
subscriber.stopAsync().awaitTerminated();
System.err.println("stopped");
for (;;) {
  Thread.sleep(1000);
}

we keep pulling messages forever. Stopping subscriber flushes waits for all messages to finish processing, but it does not stop the polling chain from continuing.